It would be very useful to be able to have separate date tags for days months and years so it is possible to format notification emails properly for inflexible email parsing programs, amongst other uses.
I understand there are options to specify dd/mm/yyyy or mm/dd/yyyy but unfortunately the program that parses the notification email assumes an american date format when /'s are used, so this is the format that I am forced to show to visitors so the dates are not mixed up when they are recorded.
You have {date_dmy} and {date_mdy} - why not have {date_d}, {date_m}, {date_y}? Same goes for the advanced date field. Then you can satisfy the needs of people who want an ISO date format, those who use dashes or slashes, those who use both i.e. dd/mm-yyyy...
Another solution would be to let people specify the exact $format of the timestamp or submitted date in the tag itself. For example a tag like {datetime_"F j, Y, g:i a"} would output March 10, 2001, 5:16 pm.
Cheers